1. Technical Field
The present invention relates to an electronic component, an electro-optical device, and an electronic apparatus.
2. Related Art
In circuit boards or liquid crystal display devices fitted to a variety of electronic apparatuses, the technique of mounting electronic components such as semiconductor ICS thereon has been used. For example, a liquid crystal driving IC chip (electronic component) for driving a liquid crystal panel is mounted on a liquid crystal display device. The IC chip may be mounted directly on a glass substrate constituting the liquid crystal panel and may be mounted on a flexible printed circuit (FPC) substrate which is fitted to the liquid crystal panel. In recent years, decrease in size or decrease in pitch of the IC chip fitted to the electronic apparatus has been required with decrease in size of the electronic apparatuses.
For example, by providing resin protrusions coated with a conductive film connected to an electrode on an active surface of an IC chip on which semiconductor devices are formed, it is possible to accomplish enhancement in reliability of the IC chip with thermal stress alleviated through pressure junction using the elastic force of resin. Here, there is known a technique for accomplishing decrease in pitch of the resin protrusions by removing a part of the resin protrusions by the use of plasma process (for example, JP-A-2004-186333).
However, when the resin protrusions are formed by the use of the plasma process, wire portions formed on the IC chip are charged up due to an antenna ratio in plasma, thereby varying characteristics of transistors. Such variation in characteristics of transistors may cause failure of the IC chip and decrease in yield.
Accordingly, a resin protrusion extending linearly is provided along respective sides of an active surface of a chip substrate constituting the IC chip and a plurality of conductive portions formed out of a conductive film connected to the pads of the IC chip are provided on the surface of the resin protrusion. In this way, it is considered that the decrease in pitch can be accomplished by the plurality of conductive portions without carrying out the plasma process for forming clearances in the resin protrusion. The resin protrusion has clearances only at the ends which are four corners of the IC chip.
When such an IC chip having the resin protrusion extending linearly is mounted on a substrate, a resin having a thickness greater than that of the resin protrusion is first provided on a mounting surface of the substrate and then the IC chip is mounted on the substrate while pressing and heating the IC chip on the substrate. Then, the resin protrusion disposed on the IC chip pushes out the resin. Accordingly, the pushed-out resin is externally discharged from the IC chip through the clearances in the resin protrusion.
In this way, the resin protrusion is electrically connected to electrodes of the substrate in the state that the IC chip is pressed on the substrate and thus the resin protrusion is crushed on the substrate. In this state, by curing the resin, the IC chip is mounted on the substrate.
However, the intermediate portions of the sides of the chip substrate without the clearances between the resin protrusions cannot smoothly discharge the resin, unlike the end portions of the chip substrate in which the clearances are disposed between the resin protrusions. That is, a larger amount of resin is discharged from the end portions of the chip substrate in which the clearances are disposed between the resin protrusions than from the intermediate portions of the sides of the chip substrate. In this way, since the resin protrusions disposed along the sides of the chip substrate have different amounts of resin discharged through the intermediate portions and the end portions, the resin protrusions cannot be provided uniformly. Accordingly, since the electrical connection property varies depending upon positions of the IC chip when the IC chip is mounted on the substrate, it is difficult to obtain reliability of the IC chip.